Attempting to get data from various groups in the regex fails

Question

I have the following regex to look for emails in a string(there might be 0 or more emails in the string).The expression has 4 groups,some of which could match a null value:

RegexPlanet Test for the expression:

          ([-A-Za-z0-9._!#$%^&*|{}'~`]+@[a-z0-9_-]+[\\.][a-z]{2,3}[\\.][a-z]{2,3})|([A-Za-z0-9.!#$%^&*|{}\"~`]+@[a-z0-9_-]+[\\.][a-z]{4})|([A-Z.a-z0-9!#$%^&*|{}'~`]+@[a-z0-9_-]+[\\.][a-z]{3})|([A-Za-z0-9.!#$%^&*_-|{}'~`]+@[a-z0-9_-]+[\\.][a-z]{2})

The code to read the data from the matcher shows an ArrayOutOfBoundsException at matchValue=matcher.group(i);

   ArrayList<String> result=new ArrayList<String>();
    Pattern pattern=Pattern.compile(regex);
    Matcher matcher=pattern.matcher(input);
    Log.d(TAG,"input: "+input);
    while(matcher.find())
    {
        String matchValue=null;
        for(int i=1;i<5;i++)
        {
            matchValue=matcher.group(i);
            if(matchValue!=null && !matchValue.equals(""))
            {    
                Log.d(TAG, "Group no: "+i+" Value: "+matchValue+" adding to result");
                result.add(matchValue);
            }
            else
            {
                Log.d(TAG, "Nothing matched for group i");
            }
        }    
    }
    return result;
}

Is there something wrong with the code or is this a side-effect of something else?

Thanking you in advance for your valuable suggestions

Answer 1

Try this:

for(int i=1; i <= matcher.groupCount(); i++)
{
    matchValue=matcher.group(i);
    ...

I am not sure why you would have a problem with the code you have, it seems to have exactly four groups, so for(int i=1; i<5; seems correct. But it is better to have the matcher tell you what the count is.

Answer 2

Do you know what input causes the exception? In general to avoid this exception you can rewrite for loop as this:

for(int i=1;i<=matcher.groupCount();i++)
        {....}